1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor laser device including a laser chip in which a semiconductor layer and electrode films are formed on the same surface of a substrate, and a mounting plate and a supporting plate which are used in the method of manufacturing a semiconductor laser device.
2. Description of the Related Art
In recent years, semiconductor light-emitting devices including a semiconductor laser device in which a nitride semiconductor such as GaN is employed as a light source for short-wavelength lights have been developed.
Generally, with the semiconductor laser device utilizing the nitride semiconductor, an n-type layer, an active layer and a p-type layer, which are made of the nitride semiconductor, are stacked in sequence on a substrate made of sapphire (Al2O3). Among a pair of electrode films of the semiconductor laser device, a p-side electrode is formed on the p-type layer which is the most upper layer in the semiconductor layer, while an n-type electrode is formed on the n-type layer which is exposed by etching the p-type layer and the active layer. Here, the substrate, the semiconductor layer, the p-side electrode and the n-side electrode are collectively called a laser chip.
In general, the laser chip is supported by a supporting plate (also referred to as a heat sink) made of a metal with relatively high thermal conductivity, in order for the semiconductor layer to release generated heat effectively. Further, a mounting plate (also referred to as a sub-mount) is provided between the laser chip and the supporting plate, the mounting plate having a lead electrode on a supporting body made with an insulating material. With the conventional method of manufacturing a semiconductor laser device, a solder adheres the mounting plate to the supporting plate and then another solder adheres the mounting plate to the laser chip.
However, with such a conventional method of manufacturing a semiconductor laser device, two steps of adhesion process need to be performed, which creates a problem such that longer time for manufacturing a semiconductor laser device is required. Further, two steps of heating process are needed in order to melt the solder, which causes deterioration in performance of the semiconductor laser device due to repetition of heating.
The present invention has been achieved in view of the above problems. It is an object of the invention to provide a method of manufacturing a semiconductor laser device capable of reducing time required for manufacture and suppressing deterioration in performance due to heating, and a mounting plate and a supporting plate.
The method of manufacturing a semiconductor laser device of the present invention includes a step for simultaneously adhering a laser chip, a mounting plate and a supporting plate to each other.
The mounting plate of the semiconductor laser device of the present invention adheres to the laser chip, in which a semiconductor layer is formed on a substrate, for use, the mounting plate including a supporting body and a first solder film and a second solder film, each of which are formed on each of a pair of surfaces of the supporting body.
The supporting plate of the semiconductor laser device of the present invention supports the laser chip, which includes a semiconductor layer, having a predetermined mounting plate in between, the supporting plate including a solder film at least on one surface of the body.
With the method of manufacturing a semiconductor laser device of the present invention, the laser chip, the mounting plate and the supporting plate simultaneously adheres to each other, whereby two steps of adhesion process are not needed.
With the mounting plate of the semiconductor laser device of the present invention, the laser chip is placed on one surface of the mounting plate and the supporting plate is placed on the other surface of the mounting plate, thus the first solder film adheres the laser chip to the mounting plate, and simultaneously the second solder film adheres the mounting plate to the supporting plate.
With the supporting plate of the semiconductor laser device of the present invention, the mounting plate is placed on one surface of the supporting plate, whereby the solder film adheres the mounting plate to the supporting plate.
Other and further objects, features and advantages of the invention will appear more fully from the following description.